Equalizer for artificial dentures



Feb. 26, 1952 s. c. RQBxNsoN EQUALIZER FOR ARTIFICIAL DENTURES 2 sHETs-sx-IEET 1 Filed Jan. 12, 1951 m. M u

Feb. 26, 1952 s. c. ROBINSON 2,587,528

FQUALIZER FOR ARTIFICIAL DFNIURFS Filed Jan. 12, 1951 2 SHEETS- SHEET 2 JNVENTOR. 5ML c. eo/A/SQA/ Patented 26; '1.952 I; I A V UNITED OFFICE l $252,587,528 IBQUAL IZBB4 Eon ARTIFICIAL DENTURES y sanllnlpbinson, Portrlnnd;OregnfVVA AliplieationfJanuamflz, 19m-Serial No. 205,724

Y 18 claims. (c1. Isja- 19) tremelylmportant. `v-Un qalsjzresfs m; n

b eo'n the idge 'Eh une in p i piaf "'incorrect angular rev50 F Referring to the drawing, and moreparticuemployed is preferably four, as is most clearly.

shown in Fig. 3. There is also a source of pressure uid, here indicated at 26, and fiow passages connecting said source to all of the cylinders in common, so that the pressure on the ridges may be equalized during functional stress by the application of a counteracting pressure from the` source 26. i

In order to maintain the desired denture space between the ridges, one of the members, preferably the lower member I4, is provided with an adjustable spacer screw 30. As is best shown in Fig. 6, the screw 30 is threadedly received in the lower member I4, and is preferably provided with a locknut 32. It will be understood that the desiredfree space has been determined by conventional methods prior to thepresent equalization operation, and that the screw 30 is set to fix this desired denture space (or slightly less fora reason explained later) so that it may be reproduced in the mouth of the patient during the present operation.

Reverting to Figs. 1, 2 and 3, the lower member I4 is preferably provided with a marking table 34, and a cooperating stylus or Gothic arch tracer 3i. Layout uid may be painted on the marking table 34 to receive a Gothic arch scribing from the stylus or tracer 36, the patient being instructed in the usual manner to assume centric and eccentric positions of the mandible. By referring to the tracing the dentist later may insure that the desired centric or eccentric relation is being maintained while the appropriate quick-setting plaster record is being made. The patient is instructed Yto biteI against the spacer pin 30, and pressureis then applied to the multiple pistons. The pressure on the pistons is inherently equalized because of the fiuid nature of the system. The pressure is lincreased until the upper member is just lifted or freed of the screw 30, which may be determined by yusing a thin feeler between the screw and the upper member, or by other methods described later. When the functional stress is counteracted by the iiuid system insteadof the screw, thepressure on the ridges is equalized,'and this equalization is obtained not only under functional stress, but also with the desired denture space, and with the upper and lower members in any desired centric or eccentric relation as determined by observation of the Gothic arch tracing.

Considering the mechanism in greater detail, and referring more particularly to Fig. 4, the lower member I4 may be an aluminum or magnesium casting covered at the bottom by means of a bottom plate 4D. The part I4 has four cylinders 42 formed therein, these being open at the bottom prior tothe addition of the bottom plate 40. The studs 24 are preferably formed integrally with the pistons 44, andthe latter are l preferably fitted with suitable piston rings, which in the present case are O type rings 46 preferably made of an oil resistant artificial rubber such as neoprene. Fig. 4 shows the pistons and studs in elevated position, but it will be understood that when not under pressure they may move down to a lower position. The cylinders are preferably vented above the pistons so that there Will be no resistance to upward movement of the pistons despite possible long accumulation of slight leakage of oil or other uid past the pistons. For this purpose small vent holes may be drilled through the top of the member I4 to the cylinders, as is indicated at 48.

The number of cylinders and studs may vary, although it is obvious that at least three should be employed in order to establish an equalized relation. I definitely prefer to employ four, two on each side, as is bestshowninsFig. 3,-in order to equalizel the functionallstress on the ridges carrying the molar and bicuspids, and also in .order to leave the front clear for observation,

manipulation and other purposes.

In the present case the pressure source is a master cylinder 5I! (Fig. 4) having a master piston 52 with a piston ring 54, which again is preferably of the O type. The rear portion of the piston is provided with a male thread 56 mating with female thread 58 on the inside of the cylinder. The rear end portion 6I!v o f the piston iis enlarged and carries a sleeve-like handle 62 which may be appropriately scored or knurled to facilitate grasping and turning the same. The parts BIJ and 62 may be secured together by means of a diametric pin 64. I t will be evident that by rotating the handle 62' the piston may be advanced, thus forcing fluid, in this case preferably a heavy oil, against the `four pistons inthe four cylinders.

To connect the source to the cylinders I proi vide a passage 66 from the cylinder 50 to an upright passage 68, which in turn connects to a U-shaped channel "I0 runningbeneath the four cylinders. Thus, referring to' Fig. 5, it-will be seen that the bottom plate 40 has an open chan--l nel 10 on its upper face, the said channel following a path lying beneath the open lower ends of all four small cylinders 42, the latter being indicated on the drawing by broken lines. The location of the vertical passage is also indicated at 68. The parts 12 and 'I4 represent two rows of holes for screws which secure the bottom plate against the member I4, as is best shown in Fig. 6. This figure also shows the rectangular shape of the-channel 'II'I when viewed in section.

The master cylinder is preferably disposed at an angle, as is best shown in Fig. 3, because of convenience in mounting thel equalizer.- in anI articulator. In Fig. 3 it will be understood 'that the portion marked 66 of the section line 4&4 happens also to show thefdirection ofqthe flow passage 66 of Fig. 4 tothe point 68 where the vertical passage is located and extends downwardly ,to the bottom channel 'I0 previously described.`

The 'outer surface or barrel of the cylinder may bey provided with a 4scale indicated at 16 in Fig. 3, and the forward edge 18 vof the handle 62 may be provided with a vernieriscale, as is also shown in Fig. 3. Thus an indication of the number of turns or the advance of the piston is available to the dentist, so that he' will have some indication of the functional stress or biting pressure being exerted by the patient. This Varies greatlyv fvromjoneA patient to anothenbut the` indication is nevertheless of value in order to reveal vthev occasional.circumstance of 'a patient. having such sore ridges vor such. ill-fitting temporary bases that only a Vfeeble bite is obtained,

' sotspaced; as;` tir just t between the-1 parts` of the spring.V holder, and". this is; also: trueof'. the'. width z africanas:

.inzwhichzcasegzthe operationzrmay rbc-interrupted until-strlen undesirable condition-is. nemediedl..

- "llieezpartcnlar .imakingtftafble- -whichzfisi hereV illustrated is a dual tablezconsistingfof.;twc: parts v .3dB-rand; allfzconnected-byffa centralportion` 80, 'beshshownzinllriga8a. Itis preferably detachably connected tthee mexnlzzer:4 I4; and` for,- this-pur:-

.posezl the; member@ I4;, is:.paci/ideel; withi a--nspring holden-168:..bestfshowrimFigsg and; 9.'. "Thiszrhas: a base portion 82 secured to member I4, asi-:by` 10 .meansfofgaescrewtlill:` .Itflisf bent.:l upward -.ait:;86,

and forward; at; .818.; and then:` terminates in.y a

crthefneck portion; 80,; which just; nts :within bead im offtheholder. Thusuthe arrar igementv is'suchzthatr the; markingV table maybe snapped intcnposition,` .andL-is veryraccuratelyeheld against movement; in anydirection vby the spring. holder, yet..-may haremos/ed- (and 1 inserted). Without.l the nsefgtoolss.

rRefer-ringgrnow .to` Eigs. 1j and. 2, thefupper member: I zrhasafpairof: orwardlyfand upwardly extending arms 96, f'which carry'bearings', 98;'1iniwhichztracers are freely---slidable- Each' tracers isv preferably ,gravity-loaded lbyy forming the; upper fend with c a. ball-shaped: weight.y H10. The.. lower.l endsfare; of.:courseLfy sharpened, tol. a

'ne point..

The member I2 is preferably depliessedforinf dented.;atz.seneral:pointsa In thezpresent. cas there.v arergthreersnche:points: indicated?.at;A IliZ;4 Fig. .2.. .These serre taf-locater the: niernber` relae tive to` thefquickesetting .plaster-record formed therebeneath.. -Itwwill be: understood ,that the bottom orsmemben I2 andthe; top of; member-v I4, are zpreliminarily.- ,coated Ywith aflubricantnorpar-tingmediumlgso that, .ther parts- I2. .and I 4-farfe readilwseparated from the;y plaster record.: pilier. the;v plaster has; set.. Because; of the.`A projection ofxtheastud's 20: andV theabosses .therearound itiisga simplematterftofrecombineg thezplaster.; rec:- ardwith..thevlower member I4; in th'eqfexaet; original relationshirrgzandirl-.z thetsarne:.Wahlber-l `causeiof ther-.depressions |132, it. is..a^; simpiewrnatter tOfIeCQmbiHei-.the upper: member-With. .they plaster record.. In; this way thettvo members and. the recordgmayrbel recom'binedioruse; in a; suitable. 55 articulator.: atf'a.. later; time; when I nalnat tnedentures:

The; plaster: is.` inserted intany desired :mannen onea'methodrbeing shown. inA Fig., 6, iii-:accordance with; which the. plaster is placed in .ax'collapsibler conev IIl4 made, for example, ofcellophaneanfd. .theil'argefend ofthe cone is rolledl upor. squeezed tonejectutheplaster into4 the space-.between-.the upper. member I2 andthe lowery member I4;

It was previously stated that pressurel isvapf plied and. increased until; the: lippen: member?v is freed. of., the: spacer; scnevvgorA central. .serewf .2-; Thisimay bedeterminedrby uee-ofranthinfeeler; as. previously explained., Another: method is indicatedfiniFig. 7inaccordancewithywhichthe tracer; lI'lfhasagv scale,`V` Illii.V formed-.onf its. shank'. The,` dentist...may. observes the Y1.oeatiortcr-v the. scalerelatiye to the bearing. .98, .whileincreasing. the pressure appliedto the equalizingI pistons.. Wheng-fanr..upwa1td-inovementgoi the; bearing, `9.8,

Iii)

relative; to; the". scagleiis;4 detected; that factzrisfan indication- .thatthekbiteor tunetionalstress-has heenftakenrioeerfbyxthepistonsx.

`Asso; far-y describedztheisource o-frpressurafluid isfa masterfcylinder."andpistonpandthefrfluidiisa heavy oil. However, thiszis;notzessential, andin Eiga'. 10:1 illustratera modification in; Whichathe uidiis: cnmpressediair; :andiin whichzzthe source offpressureisrapump; pleferably:axsimplehandr operatedi bulbi; I;I i0. This fmayfbe; ofzconventional typeinf having# afgone-Wayfinletivalve at .f one: end II2, and a one-Way discharge valve at the other end. I:I4^. The compressed air iszfedxthroughV a preferably-i long; islender, flexible tube\ IfI t,ythel other 'zend ITI 8' ofi which` is: connected: to az'ttirm I2Il screwed into` thex'neckfportion- I.22 of VValovver member |24; Except'forfthefact thatfthislower member terminates,v` at what'. would befV the: inner en d:` of .the-:master cylinder' previously "described,- the lowerimember 8.24g is identical -with;that-preh viously;` described, ithavingfa central lockable. screw 3.02for setting;v the desired. denture. space; and four studs 24 carried by small pistons;.and

'afspringxholderr 88: for receiving the lmariti-,ng

tablet. Fig. 10\ diif.ersirorn Fig. 3 in; that the marking table is ,temporarily absent; from. its spring-holder, apart. from the permanent;y omission'ofitheA master-cylinder and handle.. Itywill be understood:that the1loWerfmember I24jis em.- ployed. with an uppenmember; I Zwexactly `asd-'ireviouslyI described:

With a pneumatic system' of; this; kind, the si-mf pl'est. method'of indicating=;the: bite pressure ex,- erted` by the patient. is .to` usegfa. suitable; .pressure` vgauge Iz'in theasystem. :ASL-before, the; pressure. is .built up until. there isfan. indication: that" thel functionalgstress is beingl taken by the. studs; rather lthan, thef. .centralf' screw. This; indication may be. obtained; by means of; aV paper-feelenjor by means offmarkings; ontheA tracer, as shown..` in Fig. "7, or by'other means.y vAt that timethe reading;on-.theipressure gauge isan indication of.- Whetherforsnotthe patient isexerting adequatev bite. 'Thefdentist checks the; relativef position of= the maridible by observing" the` location` ofthe tra-sermon. the marking tableand if.- thel posit-ion is; that desired, the dentist proceeds Withinser-` tionV of" a quick-setting plaster. tofmake the de sired record. Y

While the speciiicf. dimensions of .thepafrts oftheuniti areneither crticalinorfan essential.. part of the invention, itgmaybefhelpful to .givei an exf-M ample. In therpartieu-lar example of' theinyen.-i tionillustrated the. diameter of the small cylindersis; 0.148". Theymustbe exactly alikeV in. diameter. Thepistonrings-arent the 0 type,

which;l tend to roll-as the ,piston moves. The rings have-fan.. inside# diameter ofV 11a" and. anoutside diameter: of 1A; the.thicknessr or diametepof, the; ringxmavtepial itselfv beingl 152-' The; Llshaped channel which connectsthe four cylinders togetheris: 0.065 Wide and.(l.030 deep.- 'lhemaster cylinder hasadiameter offs' Thepistonjring of-.the master, piston-.has an in,- siderdiameter-ofr 1% andan OutSdediameter-Q .thethickness or. diameterof; the ring.. mate.` rial itself beine.;

The.; overallt operatQnma-y bet described as,A :tol-A lows:

.Accurate-.impressions ofthe ridges alasecured upon which carefullyl fitted A base plates. arec'oristructed; one.. s et for .an approximate. bite,l and one set for correctedocclusal relation. reeords.-

Therst setisusedwith waxbite rims,` These are, adiustedinthe month.f9r.dentu1e space. and'.

upon the casts which are mounted in the articulator, and compound bite rims constructed thereon. The occlusal equilibrator is now set up upon these compound bite rims. It is so set that the central bearing screw contacts the upper member at desired spacing. The incisal path marker or tracer is placed in the center of the marking table. This entire set-up should not disturb the denture space as maintained inthe articulator.

Layout fluid is painted on the marking table and the base plates carrying the occlusal equilibrator are placed in the mouth. The patient is instructed to close his mouth until he feels the central bearing screw contact the upper member. He is then instructed to shift the mandible' forward and backward a number of times, keeping the bearing screw in contact, until the most distal position is reached. During this procedure the Gothic arch tracer will have made a scribing on the marking table. The patient is again instructed to shift the mandible forward and backward, and stopped when the tracer pin is at the most anterior point of the scribing. VNow the patient is instructed to open slightly and a thin parchment paper feeler is inserted between the central bearing screw and the upper member. He is instructed to close, at which time the dentist must observe that the Gothic arch tracing pin is at the most anterior point of the tracing on the tracing table. If the tracing pin is not at the most anterior point the patient has allowed the mandible to shift forward and must be instructed to allow it to drop back'until the tracer pin is at the most anterior point of the scribing. The dentist then applies pressure, instructing the patient to maintain constant bite pressure.

The dentist turns the knob or applies pressure with one hand, while pulling on the paper feeler with the other hand. When he feels the paper feeler loosen he stops, and instructs the patient to shift the mandible to the right and return to centric position. He then instructs thev patient to shift the mandible to left and return tothe centric position. The patient must maintain pressure 'at all times during the excursions of the mandible. The resultant scribings'of the Gothic arch tracer on the marking table Will be a Gothic arch secured under functional stress.

After the Gothic arch tracing is made under functional stress the calibration on the-scale is noted. This calibration determines the amount of pressure the patient can exert without overloading the tissues on the ridges. This is true because the patient will bite only as hard as the pain sensation in the tissues will allow. The dentist is aware of this tolerance limit when the parchmentpaper feeler loosens. 1

lThe patient is now instructed to drop the mandible back so that the Gothic arch tracer pin is at the apex of the scribing, and to create pressure. An index of this relationship is'obtained by inserting a quick setting plaster between the upper and lower members of the occlusal equilibrator. The dentist has now established a. functional centric occlusal relation record.

The recording of functional eccentric relation records is essentially the same. The patient is instructed to shift to protrusive, right, or left, as the case may be, and exert pressure. Plaster is linserted between the sections and the index 'is made.

The casts are now remounted in the articulator, using the centric relation record index. If the articulator is an adjustable one,'the eccentric indexes are used for the final adjustment of the articulator.

It is believed that the construction, operation, and method ofuse of my improved equalizer for making artificial dentures, aswell as the advantages thereof, will be apparent from the foregoing detailed description. The invention vprovides 'a means for creating an' equilibration of the 'occluding teeth of artiiicial dentures.` It produce'san equalization of pressures transmitted to the edentulous ridges during the process of mastication. It stablizes the trial denture bases duringl the recording of the relationships of the mandible to the maxilla in the centric and eccentric positions of the mandible. Since the stablizationof the denture bases is created by equalizationof pressures during functional stress, masticatory efficiency is greatly enhanced.

It will be apparent that while I have shown and described the invention in several preferred forms, changes may be made in the structures disclosedvv without departing 'from the scope Aof the invention as sought to be defined in the following claims.

l. An equalizer for use in the making of articial dentures, said equalizer comprising spaced, generally horizontal upper and lowermembers adapted to be used with temporary bite rims fitted to the edentulous ridges of the patient, one of said members having a plurality of small vertical cylinders with pistons and studs projecting toward and adapted to contact the other member. a source of pressure fluid, and flow passages connecting said source to all of said cylinders, whereby the pressure on the ridges may be equalized during functional stress and preparatory to the insertion of a quick-setting plaster between said upper and lower members as a record.

2. An equalizer for use in the making of artificial dentures, said equalizer comprising spaced. generally horizontal upper and lower members adapted to be used with temporary bite rims fitted to the edentulous ridges of the patient, thev lower of said members having four spaced vertical cylinders with pistons and studs projecting upward to contact the upper member, Ia source of pressure fluid, and flow passages connecting said source to all four of said cylinders, whereby the pressure on theridges may be equalized during functional stress` andpreparatory to the insertion of -a quick setting 'record plaster between said upper andy lower members.

- 3. An equalizer for use in the making of artifical dentures, said equalizer comprising spaced, generally horizontal upper and lower members adapted to be used with temporary bite-rims tted to the edentulous'ridges of the patient, one of said members having a centrally disposed adjustable screw for fixing the'desired denture space wheninvcontact with the other member, one of said members also having a plurality of spaced vertical cylinders distributed about -said egssvgses screw, eachfo'f said 'cylinders 'having -a piston and stud projecting to contact the other memberpal source of pressure fluid, and flow passages connecting said source to all of said cylinders, whereby the pressure on the ridges may be` equalized duringl functional stress preparatory to the insertion of a quick-setting record plaster between said upper and lower members.

4. An equalizer for use in the making of artificial dentures, said equalizer comprising "spaced -generally horizontal upper and lower members adapted toA be used with temporary bite rims tted to the edentulous ridges of the patient, one of said members having a plurality of spaced vertical cylinders, each of said cylinders having a piston and stud projecting to contact the other member, a source of pressure fluid, flow passages connecting said source to all of said cylinders, the lower member having a marking table,

and the upper member having a Gothic arch tracer, whereby the pressure on the ridges may be equalized during functional stress with the members in desired centric or eccentric relation preparatory to the insertion of a quick-setting record plaster between said upper and lower members.

5. An equalizer for use in the making of articial dentures, said equalizer comprising spaced, generally horizontal upper and lower members adapted to be used with temporary bite rims tted to the edentulous ridges of the patient, one of said members having a centrally disposed adjustable screw for fixing the desired denture space when in contact with the other member, one of said members also having a plurality of spaced vertical cylinders distributed about said screw, each of said cylinders having a piston and stud projecting to contact the other member, a source of pressure iiuid, iiow passages connecting said source to all of said cylinders, the lower member having a marking table and the upper member having a Gothic arch tracer, whereby the pressure on the ridges may be equalized during functional stress with the members in desired centric or eccentric relation preparatoryto the insertion of a quick-setting record plaster between said upper and lower members.

6. An equalizer for use in the making of artificial dentures, said equalizer comprising spaced, generally horizontal upper and lower members adapted to be used with temporary bite rims fitted to the edentulous ridges of the patient, the lower of said members having a centrally disposed, upwardly projecting screw for fixing the desired denture space when in contact with the upper member, said lower member also having four spaced vertical cylinders distributed about said screw, each of said cylinders having a piston and stud projecting upward to contact the' upper member, a source of pressure fluid, and flow passages connecting said source to all four o f lsaid cylinders, whereby the pressure on the ridges may be equalized during functional stress preparatory to the insertion of a quick-setting record plaster between said upper and lower members.

7. An equalizer for use in the making 'of articial dentures, said equalizer comprising spaced, generally horizontal upper and lower members adapted to be used with temporary bite rims fitted to the edentulous ridges of the patient, said lower member having four spaced vertical cylinders, each of said cylinders having a piston and stud projecting upward to contact the upper member, a source of pressure fluid, iiow passages connecting said source to all four of said cyl- `inders, said f lowerfmember raving -al'markin'g -ttedtethesedeutulousfridges ofitrieripa'tient, the lower of said members having a centrally disposed, upwardly projecting screw for fixing the desired denture space when in contact with the upper member, said lower member also having four spaced vertical cylinders distributed about said screw, each of said cylinders having a piston and stud projecting upward to contact the upper member, a source of pressure fluid, flow passages connecting said source to all four of said cylinders, said lower member having a marking table, and said upper member having a Gothic arch tracer, whereby the pressure on the ridges may be equalized during functional stress with the members in desired centric or eccentric relation preparatory to the insertion of a quick-setting record plaster between said upper and lower members.

9. An equalizer as dened in claim 2, in which the source of pressure fluid comprises a master cylinder projecting outwardly from the lower member, a master piston slidable in said cylinder, and a handle and screw mechanism for advancing said piston.

10. An equalizer as defined in claim 2, in which the source of pressure uid comprises a master cylinder projecting outwardly from the lower member, a master piston slidable in said cylinder, a handle and screw mechanism for advancing said piston, and a scale for indicating the relative advance of the piston.

11. An equalizer as defined in claim 6, in which the source of pressure fluid comprises a master cylinder projecting outwardly from the lower member, a master piston slidable in said cylinder, and a handle and screw mechanism for advancing said piston.

12. An equalizer as defined in claim 1, in which the source of pressure fluid comprises a pump mechanism, and a flexible tube leading from said pump mechanism to saidA cylinder carrying member.

13. An equalizer as defined in claim 1, in which the source of pressurefluid comprises a pump mechanism, a exible tube leading from said pump mechanism to said cylinder carrying member, and a pressure gauge connected to said system to indicate the pressure being exerted 'on the pistons. f

14. An equalizer as defined in claim 6, in which the source of pressure fluid comprises a pump mechanism, and a slender flexible tube leading from said pump mechanism to said lower member.

15. An equalizer as dened in claim 5, in which the Gothic arch tracer is freely slidable in a guide, and is provided withscore lines to indicate the position of thetracer relative to the guide, whereby an increase in free space resulting from pressure on the pistons will be indicated by relative movement of the tracer and guide.

16. An equalizer as defined in claim 8, in which 11 the Gothic arch tracer is freely slidable in a guide, and is provided with score lines to indicate the position of the tracer relative to the guide, whereby an increase in free space resulting from pressure on the pistons will be indicated by relative movement of the tracer and guide.

17. An equalizer as defined in claim 4, in which the marking table is 'a dual table, and in which there are two spaced tracers cooperating respectively with said two marking tables.

18. An equalizer as dened in claim 7, in which the marking table is a dual table, and in which there Vare two spaced tracers cooperating respec tively with said two marking tables.l

SAUL C. ROBINSON.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,706,179 McBean Mar. 19, 1929 2,562,106 Leathers July 24, 1951 

